Cant get over how inexpensive the headphone is now, a tremendous deal for a top-end product!
Virtual reality, which Im going to define as the creation of a computerized 3D environment that can be interacted with and manipulated in much the same was as the real world can, is a pretty multi-faceted concept. There are quite a few ways to allow interaction with a virtual environment (VE), but the headset is perhaps the best known.
So, the key thing that a VR headset needs to be able to do is track the movements of the users head (and, where possible, their eyes) in order to allow for better interaction with the VE. After all, if I tilt my head from where Im sitting and look at the Macho Man Randy Savage action figure that stands on my desk, the positioning of my eye line will change my perspective of the figure. So VR, in order to be convincing, needs to work on the same principle.
A good follow-up question would be why does a grown man have an action figure of Macho Man Randy Savage on his desk? But frankly, thats a story for another time...
Anyway, VR headsets commonly use two screens, one for each eye, in order to create a stereoscopic effect, which allows the illusion of depth perception to take place. A PC (or MAC) will then generate the 3D environment in response to the subjects movements (this technology is not a million miles away from the design of free roaming 3D video game environments).
Theres a really cool scene in one of my favourite guilty pleasure movies, which serves as a nice example. The scene appears in Three To Tango, starring Matthew Perry (of Friends fame) and Neve Campbell. In the scene, Matthew Perry and Oliver Platt (who work as architects), compete with a rival team for an attempt to refurbish an old building. The rival team (for trivia buffs, they are played by Dr. Cox from Scrubs and Phoebes Dad from Friends) create a lavish, all-encompassing, VR environment for their would-be employer to explore, whilst Perry & Platt use an old-timey optical illusion device to better explain theirs.
Essentially, despite appearances to the contrary, both technologies operate on the same principle. Both are, when all is said and done, optical illusions. The difference with VR is that is reacts to you as you react to it, whereas the old timey optical illusion stuff simply stays the same.
In terms of the headset, thats pretty much all its doing. It is the program (being run from the PC or MAC) that is the really clever piece of design.